336

BOOK VIII.

A— Large bowl. B— Ropes. C— Beam. D —Other large bowl which coiners

use. E— Small bowl.

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it. This bowl, when shaken, is held in one hand and thumped with the otherhand. In other respects this method of washing does not differ from thelast.

I have spoken of the various methods of washing sand which containsgrains of gold ; I will now speak of the methods of washing the material inwhich are mixed the small black stones from which tin is made 20 . Eightsuch methods are in use, and of these two have been invented lately. Suchmetalliferous material is usually found tom away from veins and stringersand scattered far and wide by the impetus of water, although sometimesvenae dilatatae are composed of it. The miners dig out the latter materialwith a broad mattock, while they dig the former with a pick. But they digout the little stones, which are not rare in this kind of ore, with an instrumentlike the bill of a duck. In districts which contain this material, if there isan abundant supply of water, and if there are valleys or gentle slopes andhollows, so that rivers can be diverted into them, the washers in summer-

20 As the concentration of crushed tin ore has been exhaustively treated of already,the descriptions from here on probably refer entirely to alluvial tin.